You can save a screenshot discord chat too. There’s nothing wrong with that. If someone published something and you want to save a copy for personal purposes, go ahead.

The difference is in what Discord’s responsibility is.

If Discord claimed to have deleted an account, then they shouldn’t still be publishing a post from a user. Especially if such a post could still be tied back to the historical user id.

I can understand why they’d want to keep the data (sometimes you need to keep an archive of posts for legal reasons - for a limited time). But making an archived post visible to the public is the problem.